Means for cooling structures that are periodically heated to elevated temperatures



J 1965 D. M. SCRUGGS ETAL 3 188,961

9 MEANS FOR COOLING STRUCTURES THAT ARE PERIODICALLY HEATED TO ELEVATEDTEMPERATURES Filed May 25, 1961 5 Sheets-Sheet 1 INTERMEDIATE COOL SIDE5 E C T l O N EIE ;L

INVENTORS GORDON D. PFEIFER DAVID M. SCRUGGS. By.

% fTTOR/VEE.

June 15, 1965 D. M. SCRUGGS ETAL 3,1 8,96

MEANS FOR COOLING STRUCTURES THAT ARE PERIODICALLY HEATED TO ELEVATEDTEMPERATURES Filed May 25. 1961 5 Sheets-Sheet 2 IE E INVENTORS GORDOND. PFEIFER. DAVID M. SCRUGGS.

E/MAW 311 June 15, 1965 o. M. SCRUGGS ETAL 3,188,961

MEANS FOR COOLING STRUCTURES THAT ARE PERIODICALLY HEATED TO ELEVATEDTEMPERATURES Filed May 25, 1961 5 Sheets-Sheet 3 INVENTORS GORDON D.PFEIFER DAVID M. SCRUGGS. By" 7W a Arron/Vs June 15, 1965 D. M. SCRUGGSETAL 3,188,961

MEANS FOR COOLING STRUCTURES THAT ARE PERIODICALLY HEATED TO ELEVATEDTEMPERATURES Filed May 25. 1961 5 Sheets-Sheet 4 INVENTORS GORDON D.PFEIFER DAVID M. SCRUGGS.

I Arron/vex June 15, 1965 D. M. SCRUGGS ETAL 3,188,961

MEANS FOR COOLING STRUCTURES THAT ARE PERIODICALLY HEATED TO ELEVATEDTEMPERATURES Filed May 25. 1961 s Sheets-Sheet s INTERMEDIATE COOL SIDEI TIP. SEC'TION. !SECTION.

/ Z a 4 g INVENTORS GORDON D. PFEIFER. DAVID M. SCRUGGS.

Arron/v5) United States Patent 3,188,961 MEANS FOR COOLING STRUCTURESTHAT ARE PERIODIEALLY HEATED T0 ELEVATED TEM- PERATURES David M. Scruggsand Gordon D. Pfeifer, both of South Bend, Ind., assignors to The BendixCorporation, South Bend, Ind., a corporation of Delaware Filed May 25,1961, Ser. No. 112,676 13 Claims. (Cl. 10292.5)

The present invention relates as indicated to means for coolingstructures that are heated to very high temperatures for short intervalsof time; and more particularly to means for cooling re-entry structures,aircraft brakes, rocket nozzles andthe like.

It sometimes occurs in structures that are heated to elevatedtemperatures for short intervals of time, that only portions of thestructure are heated above a critical temperature while other portionsremain below the critical temperature.

An object of the present invention therefore is the provision of new andimproved structure which will cause the hottest portion of the structureto be cooled by radiation,.and which will reflect or pass on thisradiation to the cooler portions of the structure.

In some instances, however, more heat is generated in the hottestportions of the structure than can be absorbed or transmitted throughthe cooler portions of the structure;

and accordingly a further principle of the present invention is theprovision of new and improved means for absorbing the heat which is inexcess of that which can be absorbed or transmitted through the coolerportions of the structure.

A further object of the invention is the provision of new and improvedstructure of the above described type which is cooled by means of amaterial which goes through a change of state, and more particularly bymeans of a solid which melts to absorb the excess heat.

In some types of structure with which we are concerned, the structure isgradually heated from a low temperature to its critical temperature overan appreciable period of time during which a certain amount of radiationor conduction to its environment outside of the structure takes place.According to further principles of the present invention new andimproved means are provided whereby substantially no heat is transmittedto the internal heat absorbing structure during the period of time thatthe structure is being raised to its critical temperature; and afterwhich time the transmission of heat to the heat absorbing structureincreases markedly to maintain the temperature below its criticaltemperature. By so doing a maximum amount ofheat is dissipated to thesurrounding environment outside of the structure, and only a minimumamount of heat is absorbed by the material which undergoes a change instate.

It is a property of radiating bodies that the amount of heat radiated isa function of the fourth power of absolute temperature; so that verylittle energy is radiated at low temperatures and a great amount of heatis radiated at elevated temperatures. Accordingly, a more specificobject of the invention is the provision of new and improved structureof the above type wherein the structure which is to be cooled transmitsits heat to the heat absorbing body solely by radiation; so that amaximum amount of heat will be transmitted from the body to be cooled tothe surrounding environment outside of its structure and therefore willnot be required to be absorbed by the heat absorbing body.

The invention resides in certain constructions and com binations andarrangements of parts; and further objects and advantages of theinvention will become apparent to those skilled'in the art to which itrelates from the following description of several preferred embodimentsdescribed with reference to the accompanying drawings forming a part ofthis specification, and in which:

FIGURE 1 is a fragmentary cross sectional view of a nose cone for are-entry structure;

FIGURE 2 is a fragmentary cross sectional view of an aircraft brakeembodying principles of the present invention;

FIGURE 3 is a plan view of an aircraft brake stator to be used in anaircraft brake of the type shown in FIG- URE 2, but which is constructedsomewhat different;

FIGURE 4 is a fragmentary cross sectional view taken approximately onlines 4-4 of FIGURE 3;

FIGURE 5 is a fragmentary cross sectional view through a rocket nozzleshowing how principles of the present invention can be utilized tomaintain the throat of a rocket nozzle below its critical temperature;and

FIGURE 6 is a fragmentary cross sectional view of a nose cone using aninternal heat reflector only.

As is indicated above, the principles of the present invention can beutilized in various types of structures which are periodically heated toelevated temperatures-one such structure is the nose cone shown inFIGURE 1. The nose cone shown in FIGURE 1 generally comprises a hollowenvelope or shell 10 which is heated to elevated temperatures by airfriction during its re-entry to the earths atmosphere. The envelope isgenerally dome shaped and is suitably bolted to the front end of therocket structure 12 with a heat insulating structure 14 interposedtherebetween. Various types of heat insulating structures can be usedand as shown in the drawing, a thin layer of bubbled aluminum oxide 16is machined out of a sheet of commercially available material, and isbolted to the outside surface of a support plate 18, which may be of anysuitable super alloy, as for example Rent: 41. Bubbled aluminum oxide isa sintered aluminum oxide material which has had a foaming agentdispersed therethrough which causes bubbles to be produced throughoutthe aluminum oxide prior to its being sintered. Rene 41 is a vacuum castnickel material containing small percentages of aluminum which formnickel-aluminide particles throughout to dispersion harden the nickel.

Any suitable material capable of withstanding high temperatures can beused for the envelope 10 provided that it also has good oxidationresistance. Materials such as molybdenum and tungsten oxidize quitereadily at elevated temperatures, and therefore are not usable withoutbeing protected in some manner. In the preferred embodiment shown in thedrawing, the envelope or shell 10 is preferably made from a chromecermet capable of prolong use in oxidizing atmospheres at 3400 F. For acomplete disclosure of this material reference may be had to the Scruggsapplication Serial No. 88,302, now abandoned.

It is a property of re-entry structures generally that the front tip ofthe structure is heated to the highest temperature; that its sidesurfaces can be relatively cool; and that the intermediate section ofthe re-entry structure will be heated to intermediate temperatures. Insome instances, depending upon the speed of re-entry etc., only the verytip of the structure will reach temperatures exceeding its criticaltemperature, and it will be possible therefore to provide a reflectivestructure internally of the envelope for reflecting radiant energy fromthe tip of the re-entry structure to the side surfaces where the heatcan be dissipated without the temperature of the side surfaces exceedingthe critical temperature. The amount of heat which can be reflected,absorbed and then re-radiated in the above described manner will ofcourse be limited; so that in more severe applications it will not bepossible to re-radiate all of the heat which is transmitted to itsenvelope. The nose cone shown in FlGURE l'is intended to be-used forthese more severe applications.-

V mathematical design for the present invention simplified. -I It willnow be apparent that the exact material 30 which cone is absorbed;according to furthenprinciples of the invention which will now bedescribed.

' The structure A shown in the; drawing for dissipating" heat from theenvelope without transmitting the same to the internal portion of therocket structure 12, general- 7 'ly comprises a coritainerZtl which ismade-iof a material which will withstand the elevated temperatures.which are involved. The container 20 maybe made of any suitable'materialsuch as stainless steel, Rene 4l,'etc. and'as shown in the drawing 'isformed :of ,the'same' chrome -cermet material that has been previouslydescribed as being used' for the. envelope '10. The container is 'formedgenerally as a comically shaped cup having a bottom which is dished tobe equidistant at. all points from the envelope '10. The top of thecontainer20is provided with suitable threads 24 by means" of which it isfastened to a top'threaded plate 26 which is suitably bolted to theou'ter surfaceof the layer of insulating material :16. 'The sidewalls ofthe container20 may be variously shaped, and

as shown in the drawing are formed conicallyl fo'r'reasons' which willlater be described. The'inside'gof the ,COIP

tainer20 is filled with a solid material which has a, high latent heatof fusiomand'which melts at a predetermined temperaturewhich-correspondsfgenerally 'andldoes not exceed the maximum temperatureT which can be used to provide the necessary heat transfer rate from theen- -velope 10 to the material .30. The formula generally used tocalculate this heat transferis generally stated "as:

f=some function '7 i V '40 Q=heat transfer rate Kzconstant A=bottomsurface of container 20 e V e =emissivity of the tipportion of thecontainer 10 e =emissivity of the surface of the bottom of the conisused in the container 20, will have to be selected so that, its meltingpointdoes not exceed the maximum T temperature, which can be utilized,and in the embodiment shown in the drawing, the material 30 is metallicberyllium which has a high-latent heat of fusion and which m'e'lts'atapproximately 2400" F. V

'It'further occurs in 'the' embodiment shown in the drawingpthat the,heat which is generated upon the intermediate section-of the nose conecan be safely reflected and emitted from the cooler side section of thecone;

and accordingly the sidewalls 28 {of the container 20 have been properlyshaped to reflect 'the heat from the interme diate section onto thecooler side section of the nose cone.

The sidewall sections 28'willhave to be variously shaped in order toprovide 'their reflective function depending upon the shapeofthenose-cone; and in the embodiment shown in the drawing are comicallyshaped. To improve the reflectivity of the outer surface of thesidewalls 28,

'ateflectiveycoating' of zirconia is provided. 1 Zirconia meltsat 4700P. so that 'it'itselfwill not be damaged by the temperature of thesurface which'it sees; and it further serves the purpose of,d-iminishingyas much as possible, the heat flow' from, the intermediatesections of the envelope-10w the material 30. Itcan now be seen "thatthe structure-A shown inthe drawing, 'cools'the intermediate sections ofthe nose ,conepby refiecting'radiant energy therefrom to the cooler sidesection of the nose cone so that neither section exceeds the criticaltemperature of which it is made; and it'will further be seen that itefficiently absorbs only that portion of the heat from the tip whichis'necessaryto keep its temperature below the critical temperature ofthe material from which it is made. Structure A thereforecausesthe'envelope 10 to radiate a maximum amount of heat to the surroundingenvironment; and it only absorbs that portion which is nemsar'y tomaintain the .tip ata safetempera-ture.

' It will be apparentlthat principles ofthepresent invention will haveuse in 'still'other types of structuresone of which will be'frictionproducing devices such as aircrafit brakes. The aircraft brake shown'inFIGURE 2 generally comprises a strut. 32 having, afshafit' 34 about Iwhich is ,rotatably journaled a wheel structure 36. The

tainer'20 which sees the tip portionof the'envelope 10 T =averageabsolute temperature of the tip portion of the envelope 10 r T =absolutetemperatureat which the material 30 changes state I V While insomeinstances the'bottom 22 of the container '20 may touch the tip oftheenvelope'lo'so that there ,is direct conduction of heat fro'rn'theenvelope 10to the material 30, in the preferred embodiment shown in thedrawing a sufiicient gap is provided sothat substantially all of theheat which reaches the material 30 .must be transmittedbyjradiationaccording' to the above given formula. From this formulaitwill be seen that very little heat will be transmitted to the material30 at low values of T --which it; should be pointed out must be. keptbelow the critical. or recrystallization I or softening temperature ofthe material from which the envelope 10 is made. It will therefore beseen that for those temperatures below thecritical T temperature, verylittle of the heat will be transmitted to the, material 30, ."so that amaximum of the heat would be rejected to, the surrounding environment ofthe envelope ,10-.this is by reason of the fact that the heat radiatedto the material 30 is a function of the fourth power of the absolutetempera- 'ture. Also by keeping Ti high as possible a maximum 7 amountof heat is transmitted to space. Inasmuch as the change of-state of" allpure materialsoccurs at .a con-.

stant temperature, it-will be seen-,that'the heat which is;

absorbed from the tip'of the envelope 10 will be absorbed constant, andthe fact that T islvconstantymakes :the'

wheel structure 36 is provided with a plurality of keys 38 equallyspaced around the outer flange 40 of the wheel.

The keys'38 are provided for the purpose of projecting intocorrespondingly positioned keyways which are formed 'into'theouterperiphery of annular rotor members 42;" The strut 32 isprovided'with a rigid flange 44 to which is suitably bolted a stationarysupport structure ,46 to which the stationary or stator elements 48 and50 of the brake "are suit'ably fixed. 'The intermost stator element 52is bolted rigidlyto the support structure 46, and the stator elements 48and 50 are formed as annuluses having suitable keyways on theirinn'ersurface sc that they are free to move axially over the boltingstructure154 of the stator element 52. It will'now be seen that thestator and rotor elements are free to move axially along theirrespective jkeyw'ays; and all of the elements are adapted/to bes'andwiched together bya plurality o1 pistons 56,] only one of whichis'sh'own, which in turn i: actuated by means of hydraulicpressure'that' is communi cated'to its hydraulic inlet connection 58.The structure 'so far described is quite conventional, and for a morrcomplete-description and understanding of this type 0 structure,reference may'be had to the DujBois Paten 2,731,312.- Each'ofrthe statorelements 48, 50 and 51 carry a pluralityof cup-shaped structures 60-which an filled with an inorganic friction material 62 of the typldescribedin the Stedman etaL, Patent 2,784,125. Thi

f material 62 carriedtby, the stator membe rs is in tun l rubbedagain'stthe side surface of the rotor members 41 'which'may be made of.any suitable high temperatun at a constant temperature. The factthat Tmust be held material as *for "example'xthe chrome cermet materia As iswell known in the art, aircraft brakes are made to handle energyexceeding 41 millions of ft./lbs. during a stop, which energy for themost part cannot be rejected to the surrounding atmosphere becausesuflicient air flow cannot possibly be provided; and this heat thereforeraises the temperature of the brake to exceedingly high temperatures.According to principles of the present invention solid materials whichwill undergo a change of state are incorporated into the brake structurefor the purpose of absorbing this heat at a constant low temperature tothereby prevent any portion of the brake structure from exceeding thecritical temperature of the materials from which the brake is made. Anysuitable material undergoing a change of state can be used. The materialmay be placed so that it sees either of the rubbing surfaces of thestator or rotor members, or as shown in FIGURE 2, can be placed so thatit sees the back side of one of the rotor or stator members.

In the embodiment shown in FIGURE 2, a separate rotor member 42 isprovided for each friction surface of the stator members 50; so that tworotor members 42 are positioned side by side with a space in between. An

, annular heat absorbing member 64 is positioned in this space and iskeyed to the wheel structure 36 along with the rotor members 42, so thatit rotates with the rotor members and no sliding occurs between therotor and heat absorbing members. The heat absorbing members 64 shown.in the drawing are formed by radially inner and radially outer rings 66and 68 which hold the rotor members 42 spaced apart, and further includeannular side plates 70 which are suitably welded to the inner and outerrings 66 and 68. The annular side plates 70 are spaced apart from therotor members 42, and are spaced apart from each other, so as to providean internal chamber that is filled with the heat absorbing material 72which undergoes a change of state. Any suitable heat absorbing solidmaterial which undergoes a change in state at a sufliciently lowtemperature to keep the rotor member 42 below its critical temperaturecan be used. In the embodiment shown in the drawing, the heat absorbingmaterial 72 is metallic aluminum, and the rings 66 and 68 and sideplates 70 are made of carbon steel. The rotor members 42 are made fromthe chrome cermet material disclosed in the Scruggs application 88,302.This material can stand a temperature of 3400 F., and the frictionmaterial 62 previously described can stand a temperature ofapproximately l800 F. It will now be apparent that the rotor members 42are kept well below their critical temperature by the aluminum whichmelts at approximately 1100 F.; and that the aluminum absorbs its heatfrom the rotor members 42 principally by means of radiation through theair space 74 between the rotor and heat absorbing members. Inasmuch asthe heat absorbing material receives its heat from the brake structureprincipally by radiation, the rotor and stator members are permitted toreach their elevated operating temperatures at which they work best,rather quickly and thereafter are maintained approximately at thistemperature by reason of the principles discussed previously withrespect to the structure in FIGURE 1.

FIGURE 3 of the drawings is a plan view of a stator member which isintended to be used in an aircraft brake structure similar to that shownin FIGURE 2. In the embodiment of brake structure utilizing the statormember 76 only one rotor member 42 is used between stator members sothat the brake structure is conventional in this respect. Cooling ofthis brake structure is had by means of heat absorbing members 78 whichare positioned between the friction material containing cups 62.

Heat absorbing members 78 are relatively thin compared to, the cupstructures 60, so that they do not rub against the surface of the rotormembers during the operation of the brake. As seen in FIGURE 3, thestator member is provided with alternate friction producing and heatabsorbing members of about the same size so that the 6 rubbing surfacesof the rotor members are maintained at an even temperature.

The heat absorbing members 78 may be made in any suitable manner and ofany suitable material and as shown in the drawing, are formed in theshape of small cylindrical disks or cookies having opposite end platesbetween which the heat absorbing material 72 is con-fined. Thecontainers 80 shown in the drawing are made of carbon steel suitablywelded together, and are inserted through openings 82 in the statormembers 76, and are suitably Welded in place. The heat absorbingmaterial may be of any suitable material as previously explained, and asshown in the drawing is metallic aluminum. With the embodiment shown inFIGURE 4, none of the heat absorbing members 64 need be provided, andonly onehalf of the rotor members 42 as seen in FIGURE 2 are provided sothat in some instances it may be possible to reduce the width of thebrake structure from the Width which would be required by the embodimentseen in FIGURE 2.

The principles of the present invention will have still other uses, oneof which will be for the cooling of the throats of rocket nozzles, asshown, for example in FIG- URE 5. The rocket nozzle shown in FIGURE 5generally comprises a throat section which may be made of any suitablematerial as for example wrought tungsten. The rocket nozzle shown is ofthe movable type whose axis can be moved to change the direction of theblast and includes a spherical section 92 which slides on a matingspherical surface 94 of the retainer plate 96. The retainer plate 96 issealingly aflixed to the casing 98 of the rocket motor by means of anysuitable structure; and the inner portion of the throat section 90 isprotected from the intense temperature of the flame by means of azirconium oxide layer 99. The trailing or diverging section of thenozzle 100 is not subjected to the intense temperatures of the flame,and to save weight is preferably made of Fiberglas reinforced orimpregnated with a phenol formaldehyde plastic. The diverging section100 is suitably bolted to the throat section 90; and in order to preventpressure leakage through the movable joint between the sphericalsurfaces 92 and 96, an annular sealing structure 102 resembling a tireis suitably posi tioned between the stationary retaining plate 96 and aremovable flange 104 that is bolted to the throat section 90 along withthe diverging section 100. The throat and diverging sections, can bemoved in any suitable manner, and as shown in the drawing, is actuatedby means of a plurality of hydraulic fluid pressure motors 106, only oneof which is shown, in a manner which will be well understood by thoseskilled in the art.

According to principles of the present invention the throat section 90is cooled by means of an annular heat absorbing body 108 which is spacedfrom and interpositioned between the throat section 90 and the sealingstructure 102 to prevent the sealing structure 102 from being heated byradiation from the throat section 90. The heat absorbing member 108 ispreferably made from a sheet, of the wrought chrome cermet materialpreviously referred to, which is bent into an annular envelope andwelded together in a manner which will be well understood by thoseskilled in the art. The envelope is provided with a flange 112 by whichit is bolted to the throat section 90 in a manner assuring an air space114 between the heat absorbing body and the throat section 90. Theenvelope is filled with a suitable solid material 116 which undergoes achange of state; and the preferred embodiment shown in the drawing isfilled with metallic beryllium. The space between the heat sink 108 andsealing structure 102 is preferably filled with an insulating material118 such as Fiberglas to prevent deterioration of the rubber from whichit is made. It will now be seen that the throat section 90 is maintainedat a temperature below its critical temperature by means of radiation tothe heat absorbing body 108, which in turn absorbs the radiation, andprevents it from being re-radinozzle section 90. r

' perature.

ated'to the annular sealing structure 102, which would normally bedamaged by the direct radiation from the FIGURE 6 of the drawings showsa nose cone similar to that seen in FIGURE 1, excepting that onlyaninternal reflector R is used to keep the external surface of the noseit mustbe: cooled at a predetermined rate, said side areas cone fromexceeding its critical temperature. Those 'portions of FIGURE 6 whichcorrespond to similar portions of FIGURE 1 are designated by a likereference numeral characterized further in that a prime mark is affixedthereto. The reflector R is generally. formed by a cone shapedsupporting structure 120 made from any suitable; high temperaturematerial such as Rene 41, and-a reflective layeror coating 122 of asuitable reflective material such as zirconia. The reflector may be heldin place in any suitable manner, and is shown reentry structure 12. Thereflective surface 124. of the as shown by the parallel dot-dash lines,and is-preferably a hyperbolic conoidal surface.

While the invention hasbeen bodiments shown and. described; and itisour, intention to cover hereby allnovel adaptations, modifications andarrangements-thereof whichcomewithin the practice of .those skilled inthe art to which the invention relates; 7

We claim: 1. In heat dissipating structure: a first body which receivesheatat a maximum rate for ashort interval of time and whose temperaturemust be kept below -a first predetermined temperature, and a second bodyspaced and positioned to receive heat energy from said first bodysubstantially entirely by radiation at said maximum rate when saidsecondbody is at a n elevatedsecond predetermined temperature, said secondbody including a solid which changes state at anelevatedtem-peraturecorresponding generally to said second predetermined temperature. I I H2. In heat dissipating structure: a first body which receives heat at amaximurnrate for a short'interval of time ,andwhose temperature must bekept below a first predetermined temperature, and a second body shapedand positioned to receive heat energy from said first body substantiallyentirely by radiation at'saidmaximum rate when said second'body is at anelevated second pre- 7 in the drawing as clamped between the nose cone10f, and the body of. the

I described in considerable detail, we do not wish to belimited to theparticular em- 7 areas of said re-entry structure.

.material 122 is designed to reflect heat from the tip of the 1 nosecone out of the cooler side surfaces of the nose cone receiving smallamounts of heat and having a sufficiently ,-high-emissivity to keepit'stemperature well below'said .first'predetermined temperature, andsaid intermediate surface receiving anintermediate amount of heat torequire only a small amount of cooling to hold its tempera- ..ture belowsaid first predetermined temperature, a body positioned inside saidhollow structure and having a front area spaced therefrom to receiveradiant'energy at said predetermined cooling rate when its temperatureis below a secondpredetermined elevated temperature, said bodycontaining-a material which changes state at a temperature correspondinggenerally to-said second predeter- ,mined temperature, and said bodyalso having reflective side surfaces for receiving said radiant energyfrom said intermediate surface areas and reflecting it to said side 6.In a nose cone and the like: .a hollow nose structure having. front,sideand intermediate surface areas which must be kept below a firstpredetermined temperature, saidjfront. area receiving large amounts ofheat so that .it must becooled at a predetermined rate, said side areasreceiving small amounts of heatand having a sufliciently high emissivityto keep its temperature well below said first predetermined temperature,and said intermediate surface receiving an intermediate amount of'heatto require only a small amount of cooling to hold its temperature belowsaid first predetermined temperature, a body positioned insidesaidhollow structureand having a front 30.,

area spaced therefrom to receive radiant energy at said predeterminedcooling rate when its temperature is below a secondpredeterminedelevated temperature, said body containing a metalwhich melts at atemperature corresponding generally ,to'said second predeterminedtemperature, andsaidbody also having conoidal reflective side surfaces'forreceiving said radiant energyfrom said intermediate surface areasand-reflecting it to said side vareas ofsaid. re-entry structure. 7

7. "In a nose cone and the like: a hollow nose structure comprising a.s-intered mixture of approximately 94% chromiumand 6% magnesia havingfront, side and inter- 'mediatesurface areas which must be kept belowapproxi- .mately 3400? F., said front Tarea receivinglarge amounts I ofheat so thatit must be cooled at a predetermined rate, "said side areasreceiving smallarnounts of heat and having .a su'fi'iciently. highemissivity to keep its temperature well determined, temperature, saidsecond body inc'luding a i a solid metal which melts at an elevatedtemperature corresponding generally to said second predetermined tem- 3.In re-entr y structure:

there being side areas of high emissivity and a considerably'lowertemperature, a reflectivesurface inside said structure and spaced fromsaid frontsurface area;.to

wreceive radiant energy only,: said reflective'surface being shapedtoreflect heat from said frontsurface area .to said side areas.

I 4.- lu-anose cone of a a first predetermined of high emissivityanda-considerably lower temperature, and a hyperbolic conoidalreflective surface inside said 'structurejspacedsaid structure includinga e ;front surface area which [receives heat at a maximum rate V for ashort interval of time and'whose temperature must Y be kept below afirst predetermined temperature, :and

below said first predetermined temperature, and said inter- .mediatesurface receiving anintermediateamount ofheat to require only a smallamountof eooling to hold. its temperature below said first predeterminedtemperature, a bodypositioned inside said hollow structure and having afront area spaced therefrom to receive radiant energy at 7 saidpredetermined cooling rate when its temperature is below a secondpredetermined elevated-temperature, saic body containing beryllium whichchanges. state at a tern perature corresponding generally to said secondpredeterfminedtemperature, and said body also having refiectivc sidesurfaces for receiving said radiant energy from saic intermediatesurface-areas and reflecting it to said Sldt areas ofsaid re-entrystructure.

8. In a friction producing'device': 'having'a pair 0 membershavingsurfaces which are rubbed together t: generate heat at apredetermined rate and first predeter mined temperature,;a body spacedfrom one of said sur faces to receive heatv by radiation at saidpredeterminer ratewhen its temperature is below a second lower pre:determined temperature, saidbody'containing a materia which changesstate at a temperature which does not ex from said front surfacearea to,receive'radiant energy V only, said reflective surface being shaped to;reflect heat from said front surface areato said side areas;

5. Ina nose cone. and. the like ahollow nosexstructure I having "front,side and" intermediate surface areas which ceed said secondpredetermined temperature.

9.'.In afriction producing device having rotor and sta tor membershaving-respectivesurfaces which-are rubbe togetherto generate heat at apredetermined rateand fir:

7 predetermined temperature, a' body spacedapart from on must bekept'below a first predetermined temperature;

.said front area'rec'eiving large amounts. ofheat so that p of saidmembers on its side opposite to its heat-generatin surface to receiveradiantenergy from said member at sai predetermined rate when itstemperature is below a second predetermined temperature, said bodycontaining a solid material which changes state at a temperature thatdoes not exceed said second predetermined temperature.

10. In a friction producing device having rotor and stator membershaving respective surfaces which are rubbed together to generate heat ata predetermined rate and tfirst predetermined temperature, a body spacedapart from one of said members on its side opposite to its heatgenerating surface to receive radiant energy from said member at saidpredetermined rate when its temperature is below a second predeterminedtemperature, said body containing aluminum which melts at a temperaturethat does not exceed said second predetermined temperature.

11. In a friction producing device having generally parallel rotor andstator plates on one or" which are fastened spaced apart metallic cupscontaining a friction producing material which rubs against the surfaceof said other plate to generate heat at a predetermined rate and firstpredetermined temperature, said one plate having a body positionedbetween said cups in a manner which does not rub against said otherplate but which receives radiant energy therefrom, said body containinga solid material which changes state at an elevated temperature toabsorb heat from said surfaces.

1 2. In a friction producing device having generally parallel rotor andstator plates on one of which are fastened spaced apart metallic cupscontaining a friction producing material which rubs against the surfaceof said other plate to generate heat at a predetermined rate and firstpredetermined temperature, said one plate having a body positionedbetween said cups in a manner which does not rub against said otherplate but which receives radiant energy therefrom, said body containingaluminum which melts at an elevated temperature to absorb heat from saidsurfaces.

13. A nozzle structure for handling fluids at predetermined elevatedtemperatures and comprising: a member forming a thin walled venturisection and made of a material which must be held below a firstpredetermined temperature, said venturi section radiating heat at apredetermined rate when it is at said temperature, and an annular bodysurrounding and spaced from said venturi section to receive radiantenergy therefrom at said predetermined rate when its temperature isbelow a second predetermined temperature, said body containing a solidmaterial which melts at a temperature that does not exceed said secondpredetermined temperature.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES1958 Missile Materials Review (Zaehringer et al.), Missiles and Rockets,vol. 3, No. 3, March 1958, pages 69-75.

Space Technology, Aviation, vol. 68, No. 16, Apr. 21, 1958, pages -59.

How We Have Progressed in Nose Cones, Missiles and Rockets, Apr. 4,1960, pages 32 and 33.

BENJAMIN A. BORCHELT, Primary Examiner. ARTHUR M. HORTON, Examiner.

1. IN HEAT DISSIPATING STRUCTURE; A FIRST BODY WHICH RECEIVES HEAT AT AMAXIMUM RATE FOR A SHORT INTERVAL OF TIME AND WHOSE TEMPERATURE MUST BEKEPT BELOW A FIRST PREDETERMINED TEMPERATURE, AND A SECOND BODY SPACEDAND POSITIONED TO RECEIVE HEAT ENERGY FROM SAID FIRST BODY SUBSTANTIALLYENTIRELY BY RADIATION AT SAID MAXIMUM RATE WHEN SAID SECOND BODY IS ATAN ELEVATED SECOND PREDETERMINED TEMPERAURE, SAID SECOND BODY INCLUDINGA SOLID WHICH CHANGE STATE AT AN ELEVATED TEMPERATURE CORRESPONDINGGENERALLY TO SAID SECOND PREDETERMINED TEMPERATURE.